Well I ended up buying a GS-911 and here are the fault codes.
3 fault codes found:
24052 Electrical System under-voltage
The fault is not present now.
24048 Power Supply to Pump motor faulty
The fault is not present now.
24049 Power Supply to Pump motor faulty
The fault is not present now.
I've cleared the faults so I'll see what happens, the fault light only illuminated that once so it might be a one off. I also ran the GS-911 ABS pump test and could hear the motor turning so it's working at the moment.
The battery was replaced late last year.
Steve